Fuse



p c. E. o. KRIEGSTEDT FUSE Filed May 6, 19

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memes Sept. 19, 1933 FUSE Carl Erenest Oscar Kriegstedt, Washington, D.0., assignor to Engineering Appliance Corporation, Baltimore, Md., acorporation of Delaware Application May 6, 1932. Serial No. 609,723

6 Claims. (01. 200-12 1) The present invention relates to electric fusescapable of visibly indicating the inoperativeness of the same after ithas become blown, having among its principal objects to provide a self-5, contained unit in which is included a signal lamp and fuse element,all of which can be manufactured and assembled at a comparatively lowcost to render the same commercially desirable.

Another and equally important object of the present invention is toprovide a renewable fuse for installation in a lighting circuit having alight signal capable of being visible when the fuse element is blown andthe glow from the lamp to be sufficient to illuminate the fuse in orderthat the operator may readily refill or replace the fusibleelementthereof.

Still another object of the invention is to provide a plug fuse capableof being installed in an ordinary electric light circuit and which whenso 0 installed may have its-fusible element renewed without removing theplug fuse from the socket of the lighting circuit in which it isincluded.

,With the above and ,other objects in view the invention consists of thenovel features of construction, combination and arrangement of parts aswill be hereinafter more fully described and particularly pointed out inthe accompanying drawing in which:

Figure 1 is a vertical section through the plu fuse embodying one formof my invention;

Figure 2 is a detail perspective view of the combined partition andlight holder having arranged therein a miniature lamp;

Figure 3 is a vertical section through the plug fuse taken at rightangles to that shown in Figure 1 and illustrating another form of theinvention;

a Figure 4 is a detail perspective view of the combined lamp holder andpartition as is employed in that form of the invention shown in Figure3;

v Figure 5 is a detail side elevation of the removable plug having thefuse element attached thereto, and

' Figure 6 is a horizontal section taken on the w line 66 of Figure-5 inthe direction of the arrow pointa'.

Referring now. more particularly to the accomnanyi s drawing whereinlike corresponding parts are designated'by similar reference charastersthroughout the several views, 1 have herein shown a plug fuse capable ofbeing inserted in a standard socket of an electric wiring system andcomprising a body portion 1 which is preferably molded' in one piecefrom porcelain or the like insulating material. Surrounding this meansof a resistance 15 whereby a miniature body portion 1 is a ferrule orcovering 2 preferably made of brass, which is capable of engaging thesocket included in the lighting system inwhich the fuse is to be used.The axially positioned contact or terminal of the fuse is formed bymeans of the rivet 3 which is secured within the lower portion of thebody 1 and is adapted to. be connected to the ferrule terminal 2 bymeans of the fusible element 4. This fusible element 4 has one endsoldered as at 5 to the inner end of the rivet 3 whereas the oppositeend of this fusible element 4 is secured by the solder 6 to the terminal2 whereby the latter will be retained in place about the body portion 1of the fuse.

The body portion 1 of the fuse is of hollow construction forming anenlarged chamber 7 in which lies the fusible element 4 and this chamber7 being of relatively large area, permits the gases to readily expandtherein, which gases are given 011 by the fusible element 4 when thelatter has been ruptured or blown. Also electrically connected to thisrivet terminal 3 is a conductor 8 which lies within a recess formed inthe body portion 1 of the fuse and after the conductor 8 is laid withinthis recess, a suitable covering of insulating material, hereinindicated by the numeral 9, is placed over the condoctor 8 andcompletely fills the recess formed within the body portion 1. The upperend of the body portion 1 is enlarged and has formed therein a circularcompartment 10 and in this compartment 10 is adapted to be seated thecombined lamp holder and partition 11. This partition 11 ispreferablymolded from porcelain or a similarinsulating material and hasformed therewith a depending skirt or flange 12 which is seated withinthe upper end of the compartment 7 whereas the remaining portion of thispartition 11 is seated within the compartment 10 of the fuse body.Formed within the upper part of the partition 11 is a recess 13 andadapted to be seated within this recess is a miniature lamp 14. Thislamp 14 is preferably one which contains a low potential mixture ofinert gases and one electrode arranged in the lamp is connected to theconductor 16. This conductor 16 is electrically connected to theconductor 8 by glow lamp containing a low potential mixture ofinertgases, may be employed, irrespective of the voltage within thelighting circuit in which this fuse is to be included. The otherelectrode of the lamp 14 is connected to a conductor 17 l and the latteris electrically connected to the terminal 2 by means of the soldering 6.The

.14 arranged within the fuse.

terminal 17 together with the fusible element 4 extends through anopening 17 formed within the body 1 so as to have engagement with theterminal 2.

The upper opened end of the bodyportion 1 of the fuse is closed by meansof a cover made of any suitable transparent or translucent material or amica disk 18 as herein shown in order to form a display window for thelamp This mica disk 18 is secured in position by the ring or cap 19which latter is crimped about the bead-20 formed -withthe upper end ofthe body portion 1.

In assembling my improved fuse during the course of manufacture thereof,the casing or body member 1 of insulated material having the rivet 3secured therein, has inserted thereover the threaded band or terminal 2and the fusible element 4 connects the rivet 3 with this terminal 2 Iwhereby the latter is retained in permanent position about the body 1.The conductor 8 is also electrically connected to this rivet 3 andpositioned within the recess formed in the body 1. The partition 11 isthen inserted in the upper end of the body 1 and by inserting the lamp'14 within this partition, connecting its conductors with the ring 2 andthe conductor 8, the partition and lamp will be retained in position inthe fuse. Finally the mica disk is fastened about the upper opened endof the fuse by means of the connecting band 19 whereupon the fuse isreadily presented for use. By providing comparatively few parts andfollowing the aforesaid mode of assembling the parts of the fuse, itwill readily be seen that the cost thereof will be materially reduced.

Whereas in the foregoing, I have described my fuse as being one whichwhen the fusible element has been ruptured or blown may, in itsentirety, be discarded and a new fuse substituted therefor, I have foundit desirable at times to provide a renewable fuse wherein a fusibleelement may be substituted for the one blown without discarding theentire fuse casing, and in Figures 3, 4, 5 and 6 of the drawing, I havedisclosed another form of fuse with a renewable fusible element appliedthereto. In this form of the invention, the mica disk 18 as well as thepartition 11 each have an opening extending therethrough and the openingwithin the partition 11 is herein designated by the numeral 21, throughwhich is adapted to extend, a plug 22. This plug 22 is preferably madeof fiber or similar insulating material and has attached thereto afusible element 23. In order to connect this fusible element 23 to theplug 22, I provide about the latter, a threaded conductor ring 24 and acap 25 which latter retains the strip 23 of fusible material to the plugso that when the plug is inserted in the fuse casing, the cap 25 willcontact with the inner face of the rivet terminal 3 and the threadedring 24 is capable of having electrical connection with the terminal 2located about the casing 1 of the fuse. In order to form an electricalconnection between the threaded ring 24 and the terminal 2, I provide aplate 26 which rests against the lower face of the partition 11 and hasa threaded sleeve 27 extending within the opening 21 of the partition sothat the threaded ring 24 may engage this internally threaded sleeve 27of the plate when the plug is inserted within the fuse. A strip 28extends from this plate 26 and is connected by means of solder 29 to theterminal 2, whereby when a plug with the fusible strip applied theretois inserted within the fuse casing, an electrical connection may beestablished between the contacts 2 and 3.

One of the electrodes of the lamp 14 positioned.

connected thereto is also connected to the plate 26 in order that shouldthe fusible strip 23 be ruptured or blown, the current will flow throughthe lamp 14 therebygiving off a visible signal that the fuse has beenblown. After the fuse has been blown, it is only necessary that theoperator grasp the handle or knob 30 of the plug 22 and by turning thelatter until the ring 24 is out of engagement with the sleeve '27,remove the plug and fusible element fromthe fuse. A new plug or a newfusible element of strip 23 applied to the old plug may be insertedwithin the fuse, whereupon a new connection will be established betweenthe terminals 2 and 3 and the lighting circuit in which the fuse isincluded will be again complete without removing the fuse body' from thesocket of such lighting circuit.

Very often plug fuses of this character when included in the fightingcircuit, are arranged within a box in some dark corner of a building andaccordingly, it is quite. obvious that by providing a lamp within thefuse, the visible signal will be readily apparent should the fuse becomeblown. In the renewable fuse herein described,

the lamp not only functions as a telltale signal. but the glow from thelamp is sufficient for the operator to readily find the opening withinthe fuse in which the plug 22 may be withdrawn or a plug with a newfusible element therein inserted.

Manifestly, the construction herein shown is capable of considerablemodification and such modifications as come within the scope of myclaims, I consider within the spirit of my invention.

I claim:

1. A fuse device comprising a body having contact terminals capable ofhaving electrical engagement with a standard socket of an electriclighting system whereby one end of the body portion of the fuse willextend from the socket and be exposed, of a removable fuse elementadapted to have contact with the terminals of the fuse body wheninserted therein, a lamp connected across said terminals for visiblyindicating the rupture of said removable fuse element, and said lampbeing so positioned as to illuminate the exposed end of the fuse bodywhen said fusible element has been removed from the fuse nection betweensaid plug and fuse body having threads of a less pitch than that of thethreads of said threaded shell, whereby said plug may be released fromits threaded engagement with the fuse body without turning the threadedshell when the latter is applied to the usual threadedsocket of thelighting system.

3. A plug fuse comprising a circular body portion, a threaded shellsurrounding said body portion and serving as a contact for the fuseplug, a centrally arranged contact button mounted masses 3 within thefuse body, said fuse body having an op ning arrangedtherein and arrangedeccen trically thereto, a plug, a fusible element carried by said plugand adapted to bridge said contact members when inserted within theopening of the fuse body, and a detachable connection be tween said plugand said fuse body.

4. An electric fuse comprising a casing, an axially positioned terminalsecured within said casing, a terminal arranged aboutsaid casing, apartition supported within said casing and having an opening therein, aplug capable of being in= serted through the opening of said partition,a fusible element carried by said plug and adapted to have contact withthe terminals of said casing when inserted therein, and a visible signalar= ranged within said partition capable of indicat ing theinoperativeness of said fusible element.

5. ,A fuse plug comprising a casing, terminals arranged about saidcasing, a partition arranged within said casing'and having an openingthere in, a conductor plate carried by said partition and havingelectrical connection with one of the tar minals of said casing, a plugcapable of being inserted through the opening of said partition,

a fusible element carried by said plug and having electrical contactwith said contact plate and the other of said terminals, a glow lamppositioned within said partition, and conductors connecting said glowlamp with the terminals of said casing.

6., A fuse device comprising a hollowed shell, a threaded contactterminal surrounding said shell and capable of having electricalengagement with a standard socket of an electric light= ing systemwhereby one end of said shell will extend from the socket and beexposed, a button contact terminal carried by said shell, a removablefuse element adapted to have contact with said contact terminals wheninserted with in the shell of the fuse, said shell having an opened end,a lamp arranged within the open end of said shell and connected acrosssaid termimale for visibly indicating the rupture of said removablefusible element, a transparent covering for closing the opened end ofsaid shell, and said lamp being so positioned as to illuminate theexposed end of the fuse when said fusible element has been removedtherefrom.

-. III

